CN104094565A - Controller, method for distributing load, non-transitory computer-readable medium storing program, computer system and control device - Google Patents

Abstract

A plurality of controllers (1) are positioned in an open-flow network. Each of the controllers (1) is provided with a load management table (153) and a load control unit (14). The load management tables (153) manage, for each of the switches (2) saved in the open-flow network, the number of messages transmitted during each prescribed interval of time to the controllers (1) for managing the switches (2), and/or the number of packages received during each prescribed interval of time by the switches (2). When a prescribed event occurs, the load control units (14) detect the controllers (1) for which the processing load is at or above a first threshold, on the basis of the load management tables (153), and switches at least one switch (2) being managed by a detected controller (1) to management by a different controller (1).

Description

Controller, method for distributing load, non-transitory computer-readable medium storing program, computer system and control device

technical field

The present invention relates to a controller, a load distribution method, a non-transitory computer-readable medium storing a program, a computer system, and a control device. In particular, the present invention relates to a controller, a load distribution method, a non-transitory computer-readable medium storing a program, a computer system, and a control device related to an OpenFlow (OpenFlow) network.

Background technique

The OpenFlow network is a network control technology that defines a series of communications determined by a combination of a Media Access Control (MAC) address, IP address, and port number as a "flow" and performs path control for each flow. The OpenFlow network includes a controller (OFC: OpenFlow Controller) for calculating a path of a packet, a switch (OFS: OpenFlow Switch) for forwarding a packet, and terminals connected to the switch.

Each switch includes, for each flow, a flow table describing a packet forwarding path, a packet forwarding method, and the like. The controller sets packet forwarding rules in the flow table entries of the switch. Each switch forwards packets according to the forwarding rules set in the flow table.

The controller and switch are connected via Secure Sockets Layer/Transport Layer Security (SSL/TLS) or Transmission Control Protocol (TCP) called a secure channel. OpenFlow protocol messages are transmitted or received via a secure channel.

When a switch receives a packet from a terminal, the switch refers to a header field (header field attribute) of the flow table and searches for an entry having a header field matching header information of the packet. If such an entry exists, the switch updates the statistics for that entry ("Counter" attribute) and performs specified processing ("Action" attribute). If no such entry exists, the switch transmits the packet to the controller (packet-in message).

The controller receives the packet-in message and calculates the path of the packet. Then, according to the calculated path (flow-mod message), the controller adds an entry corresponding to the packet to the switch's flow table. The controller then transmits the packet to the switch (packet-out message).

If in an OpenFlow network, more endpoints are connected to the switch, the switch transmits more packet-in messages to the controller. In this case, a single controller may not be able to process the message. For this purpose, it is better to install multiple controllers in an OpenFlow network in order to distribute the messages received by the controllers from the switches.

In installing multiple controllers in an OpenFlow network, each controller is assigned a switch controlled by that controller. Thus, each controller only transmits messages to or receives messages from the switches controlled by it. Thus, messages received by the controller from the switches can be distributed.

Assuming that a plurality of controllers are installed in an OpenFlow network, each controller requires path information and topology information as described below when setting forwarding rules in the flow table of each switch. To this end, the controller synchronizes these sets of information with each other.

(1) Path information

The path information is information indicating the shortest path in the OpenFlow network. Each controller calculates path information from topology information.

(2) Topology information

Topology information is information about connections of switches in an OpenFlow network. Each controller obtains topology information about each switch controlled by the controller by periodically transmitting Link Layer Discovery Protocol (LLDP) query packets, etc., to the switches

reference list

patent documents

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2011-166692

non-patent literature

[Non-Patent Document 1] OpenFlow Switch Specification Version 1.1.0Implemented (Wire Protocol 0x02) February 28, 2011, [retrieved on January 16, 2012], Internet

<URL: http:

//www.openflow.org/documents/openflow-spec-v1.1.0.pdf>

Contents of the invention

technical problem

As described above, it is possible to install multiple controllers in an OpenFlow network and thereby distribute the load of the controllers. However, simply assigning approximately the same number of switches to each controller does not allow for load balancing of the controllers. For this, there are the following reasons (1) and (2).

(1) The use status of the switch

The number of messages that a switch controlled by a controller transmits to the controller varies from switch to switch. The number of messages also varies with time zone.

(2) Update of network configuration (topology)

The number of messages transmitted to the controller by the switches controlled by the controller varies with changes in topology configuration caused by connection failures between switches, addition or deletion of switches, and the like.

In view of the above-mentioned problems, the present invention has been made, and its main purpose is to provide a controller capable of balancing the load of the controllers, a method of distributing loads, and a non-transient computer program stored program in an OpenFlow network including a plurality of controllers. Read media, computer systems and control equipment.

Technical solutions

According to an aspect of the invention, a controller for controlling some of a plurality of switches in an OpenFlow network, the controller includes:

a load control table configured to control at least one of the following: the number of messages each of the switches in the OpenFlow network has transmitted to the controller controlling the switch within a predetermined time, and the the number of packets that have been received in the predetermined time period; and

load control means configured to, when a predetermined event occurs, detect a controller to which a processing load should be allocated based on a load control table, and cause at least one of the switches controlled by the detected controller to be at under the control of another controller.

According to an aspect of the invention, a method for distributing the load of a controller controlling some of a plurality of switches in an OpenFlow network, the method comprising:

a control step of controlling a load control table including at least one of the following: the number of messages each of the switches in the OpenFlow network has transmitted to a controller controlling the switch within a predetermined time, and the number of packets the switch has received within a predetermined period of time; and

A load control step of, when a predetermined event occurs, detecting a controller to which the processing load should be allocated based on the load control table, and bringing at least one of the switches controlled by the detected controller under the control of another controller .

According to an aspect of the present invention, a non-transitory computer-readable medium storing a program causing a computer to execute a method for distributing a load of a controller controlling some of a plurality of switches in an OpenFlow network, the method The law includes:

a control step of controlling a load control table including at least one of the following: the number of messages each of the switches in the OpenFlow network has transmitted to a controller controlling the switch within a predetermined time, and the number of packets the switch has received within a predetermined period of time; and

A load control step of, when a predetermined event occurs, detecting a controller to which the processing load should be allocated based on the load control table, and bringing at least one of the switches controlled by the detected controller under the control of another controller .

According to an aspect of the present invention, a computer system includes:

a plurality of switches, each switch configured to forward packets in the OpenFlow network according to the flow table; and

a plurality of controllers, each controller configured to control some of the switches,

Each of these controllers includes:

a load control table configured to control at least one of the following: the number of messages each of the switches in the OpenFlow network has transmitted to the controller controlling the switch within a predetermined time, and the the number of packets that have been received in the predetermined time period; and

load control means configured to, when a predetermined event occurs, detect a controller to which a processing load should be allocated based on a load control table, and cause at least one of the switches controlled by the detected controller to be at under the control of another controller.

According to an aspect of the present invention, an apparatus for controlling a load for distributing a plurality of controllers, the controllers controlling switches in an OpenFlow network, the controlling apparatus comprising:

a load control table configured to control at least one of the following: the number of messages each of the switches in the OpenFlow network has transmitted to the controller controlling the switch within a predetermined time, and the the number of packets that have been received in the predetermined time period; and

load control means configured to, when a predetermined event occurs, detect a controller to which a processing load should be allocated based on a load control table, and cause at least one of the switches controlled by the detected controller to be at under the control of another controller.

Beneficial effect

According to the present invention, a controller capable of balancing loads of controllers, a load distribution method, a non-transitory computer-readable medium storing a program, a computer system, and a control device can be provided in an OpenFlow network including a plurality of controllers.

Description of drawings

FIG. 1 is a block diagram showing the structure of an OpenFlow network according to a first embodiment;

2 is a block diagram showing the structure of the controller according to the first embodiment;

FIG. 3 is a schematic diagram showing the structure of a load control table according to the first embodiment;

FIG. 4 is a block diagram showing the structure of the switch according to the first embodiment;

FIG. 5 is a flowchart showing a control operation of the controller according to the first embodiment;

6 is a flowchart showing load information update processing performed by the controller according to the first embodiment;

7 is a flowchart showing load distribution processing performed by the controller according to the first embodiment;

8 is a flowchart showing a process of adding a switch to the OpenFlow network according to the first embodiment;

9 is a flowchart showing controller information obtaining processing performed by the switch according to the first embodiment;

FIG. 10 is a flowchart showing a process of deleting a switch from the OpenFlow network according to the first embodiment;

11 is a block diagram showing the structure of the OpenFlow network according to the first embodiment;

FIG. 12 shows an example structure of a load control table according to the first embodiment;

FIG. 13 shows an example structure of a load control table according to the first embodiment;

14 is a block diagram showing the structure of the OpenFlow network according to the first embodiment;

Fig. 15 is a block diagram showing the hardware structure of the controller according to the first embodiment; and

FIG. 16 is a block diagram showing the structure of an OpenFlow network according to the present invention.

Detailed ways

first embodiment

Embodiments of the present invention will now be described with reference to the accompanying drawings. First, an OpenFlow network according to the present embodiment will be outlined. FIG. 1 is a block diagram showing the structure of an OpenFlow network according to the present embodiment.

The OpenFlow network includes a plurality of controllers 1 (1-1, 1-2), a plurality of switches 2 (2-1 to 2-4), and a plurality of terminals (3-1 to 3-8). The controller 1-1 controls the switches 2-1 and 2-2. Specifically, it controls the flow tables of these switches and so on. Similarly, controller 1-2 controls switches 2-3 and 2-4. Specifically, it controls the flow tables of these switches and so on. Of course, the controllers 1-1 and 1-2 can control any number of exchanges. Hereinafter, the controllers 1-1 and 1-2 will be simply referred to as "controller 1" unless it is necessary to distinguish these controllers from each other.

The switch 2-1 includes a flow table. The switch 2-1 is a device that receives packets from the terminals 3-1 and 3-2 or another switch 2-2, and forwards the received packets according to the flow table. Of course, the switch 2-1 can receive packets from any number of terminals. The switches 2-2 to 2-4 are similar in structure to the switch 2-1. Hereinafter, the switches 2-1 to 2-4 will be referred to as "switch 2" unless it is necessary to distinguish these switches from each other.

Terminal 3-1 transmits or receives packets. The terminal 3-1 is, for example, a general-purpose personal computer, a mobile phone, or the like. The same applies to terminals 3-2 to 3-7. Hereinafter, the terminals 3-1 to 3-8 will be referred to as "terminal 3" unless it is necessary to distinguish these terminals from each other.

Next, referring to FIG. 2, the internal structure and operation of the controller 1 will be described. FIG. 2 is a block diagram showing the internal structure of the controller 1 . The controller 1 includes a message control unit 11 , a path control unit 12 , a topology update unit 13 , a load control unit 14 and a network information storage unit 15 . The controller 1 only needs to be a computer including a central processing unit (CPU) and the like.

The network information storage unit 15 stores path information 151 , topology information 152 and a load control table 153 . Path information 151 includes so-called "flow information" indicating how each switch 2 transmits packets. Topology information 152 indicates the structure of the OpenFlow network. The load control table 153 is a table storing information for grasping the state of the load of each controller 1 . The load control table 153 will be described later with reference to FIG. 3 .

Between all controllers 1, the information sets in the network information storage unit 15 are synchronized (the controllers 1 inform each other of any changes in the information sets). That is, when any information in the network information storage unit 15 of one controller 1 is updated, corresponding information in each of the network information storage units 15 of the other controller 1 is similarly updated.

The message control unit 11 is a processing unit that transmits or receives various types of messages defined by the OpenFlow network protocol with the switch 2 controlled by the controller 1 . Based on the received message, the message control unit 11 instructs the processing units (path control unit 12, topology update unit 13, load control unit 14) to perform processing.

The path control unit 12 receives the packet-in message from the switch 2 through the message control unit 11 . Then, the path control unit 12 refers to the topology information 152 and calculates a path from the packet-in message. Then, the route control unit 12 updates the route information 151 according to the calculated route.

The topology updating unit 13 obtains information on the connection of each of the switches 2 controlled by the controller 1 by transmitting an inquiry packet to the switches 2 . Then, the topology updating unit 13 updates the topology information 152 according to the obtained connection information.

The load control unit 14 refers to and updates the load information in the load control table 153 . When a predetermined event (passage of a predetermined time, addition or deletion of a switch 2, etc.) occurs, the load control unit 14 calculates the processing load of each controller 1 and detects a controller 1 with a high processing load. Then, the load control unit 14 determines whether the detected processing load of the controller 1 should be distributed. If it is determined that the processing load should be distributed, the load control unit 14 places some of the switches 2 controlled by the detected controller 1 under the control of the controller 1 having a low processing load. Details of the processing load distribution processing will be described later with reference to FIGS. 6 and 7 .

FIG. 3 is a schematic diagram showing the structure of the load control table 153 . The load control table 153 is a table having a switch ID, a controller ID, a hop count, a received message count, and a received packet count as attributes. The load control table 153 has entries corresponding to switches in the OpenFlow network.

The switch ID is an attribute for uniquely identifying the switch 2 in the OpenFlow network and is information used as a primary key of the load control table 153 . The switch ID is, for example, a data path ID consisting of 48 bits of the MAC address of the switch 2 , 12 bits depending on the implementation. After the secure channel is established, the controller 1 can obtain the data path ID of the switch 2 by exchanging OpenFlow protocol Features/response messages with the switch 2 .

The controller ID is an attribute for uniquely identifying the controller 1 in the OpenFlow network. The controller ID may be, for example, the Internet Protocol (IP) address of the controller 1 .

The hop count is an attribute indicating the hop count between the controller 1 and the switch 2 (the number of communication devices through which a packet passes).

The received message count is an attribute indicating the number of messages that the controller 1 has received from the switch 2 within a predetermined time. Each time controller 1 receives a message from switch 2, the received message count is incremented (+1).

The received packet count is an attribute indicating the number of packets that the switch 2 controlled by the controller 1 has received from the terminal 3 or the adjacent switch 2 . The controller 1 can grasp the number of packets received by each port of the switch 2 within a predetermined time by transmitting or receiving OpenFlow protocol statistics request/response messages with the switch 2 .

Next, referring to FIG. 4, the internal structure and operation of the switch 2 according to the present embodiment will be described. FIG. 4 is a block diagram showing the internal structure of the switch 2 according to the present embodiment.

The switch 2 includes a packet control unit 21 and a message control unit 22 . Switch 2 stores flow table 23, switch ID 24 and controller information 25. The controller information 25 includes a controller ID 251 and a hop number 252.

When packet control unit 21 receives a packet from terminal 3 or adjacent switch 2, it refers to flow table 23, determines the destination of the received packet, and then forwards the packet to the destination. When a new switch 2 is added to the OpenFlow network, the packet control unit 21 obtains controller information 25 in the adjacent switch 2 by transmitting an inquiry packet to the switch 2 .

The message control unit 22 transmits or receives messages defined by the OpenFlow protocol with the message control unit 11 of the controller 1 . When the message control unit 22 receives a flow-mod message from the controller 1, the flow table 23 is updated according to the received message. In addition, when the switch 2 establishes a secure channel with the controller 1, the message control unit 22 transmits the switch ID 24 to the controller 1.

The flow table 23 is information set by the controller 1 . For each communication flow in the flow table 23, a packet forwarding path, a packet forwarding method, and the like are described. For details, see, for example, Non-Patent Document 1.

The switch ID 24 is information for uniquely identifying the switch 2 . The controller ID 251 is information indicating the ID of the controller 1 of the control flow table 23. The hop count 252 is the hop count between switch 2 and controller 1 .

Next, referring to FIGS. 5 to 7 , the operation of the controller 1 will be described. As described above, when a predetermined event (passage of a predetermined time, etc.) occurs, the load control unit 14 of the controller 1 executes processing of distributing the load of each controller 1 (load distribution processing). Hereinafter, the load distribution processing and related operations of the controller 1 will be described in detail.

FIG. 5 is a flowchart showing the control operation of the controller 1 . The controller 1 waits for a predetermined time to elapse (step A1). After a predetermined time elapses, the controller 1 executes load information update processing (FIG. 6) (step A2).

FIG. 6 is a flowchart showing details of load information update processing performed by the controller 1 . First, the topology update unit 13 of the controller 1 obtains information on the connection of each port of each switch 2 controlled by the controller 1 by transmitting an inquiry packet to the switch 2 (step B1). If the controller 1 detects the switch 2 (hereinafter referred to as switch S0 ) having a connection failure (step B2 : Yes), the topology update unit 13 notifies the load control unit 14 of the switch S0 . Then, the load control unit 14 calculates the processing load of each controller 1 in the OpenFlow network to obtain the ID of the controller 1 (hereinafter, referred to as controller C0 ) having the lowest processing load (step B3 ). Note that a method of calculating the processing load will be described later with reference to FIG. 7 .

Furthermore, the load control unit 14 sets the ID of the controller C0 in the "controller ID" attribute of the entry of the switch S0 in the load control table 153 (step B4). The load control unit 14 of the controller C0 also sets the ID of the controller C0 in the controller ID 251 of the switch S0 through the secure channel (step B5).

The load control unit 14 of the controller 1 also obtains received packet counts from each of the switches 2 controlled by the controller 1 and sets them in the load control table 153 (steps B6, B7). At this time, the load control unit 14 excludes the number of received packets of ports that have not been used due to a change in topology. Thanks to the steps B1 to B7 above, the connection failure has been eliminated and the received packet count has been obtained. In this state, controller load distribution processing is performed (step B8). Fig. 7 shows details of the load distribution processing (step B8).

The load control unit 14 refers to the load control table 153 and calculates the processing load of each controller 1 . For example, the load control unit 14 calculates the processing load in the form of numerical information by multiplying the received message count and the received packet count. Then, the load control unit 14 obtains the ID of the controller 1 (hereinafter, referred to as controller C1 ) having the highest processing load (step C1 ).

Note that the processing load is not necessarily numerical information, but may be information such as "high", "medium", or "low" based on a predetermined threshold.

Then, the load control unit 14 determines whether or not the processing load of the controller C1 is less than or equal to a predetermined threshold (first threshold) (step C2). If the processing load is less than or equal to the predetermined threshold (step C2: YES), the load control unit 14 ends the processing.

On the contrary, if the processing load of the controller C1 is not less than or equal to the predetermined threshold (step C2: No), the load control unit 14 selects the controller 1 having the lowest processing load (hereinafter, referred to as controller C2) and obtains its ID ( Step C3).

Then, the load control unit 14 selects a switch 2 having relatively little influence on the processing load (hereinafter, referred to as a switch S1 ) from among the switches 2 controlled by the controller C1 and obtains its ID (step C4 ). In other words, the load control unit 14 selects the switches 2 in ascending order of influence on the processing load. For example, when the load control unit 14 executes step C4 for the first time, the switch 2 having the least influence on the processing load is selected as the switch S1.

Then, the load control unit 14 obtains the hop count of the switch S1 from the load control table 153 and determines whether the obtained hop count is greater than or equal to a threshold value (second threshold value) (step C5). If the hop count is not greater than or equal to the threshold (step C5: NO), the load control unit 14 returns to step C4. At this time, the load control unit 14 selects the switch 2 having the smallest processing load next to the switch S1 selected in the previous step C4.

If the hop count is greater than or equal to the threshold (step C5: Yes), the load control unit 14 sets the ID of the controller C2 in the "controller ID" attribute of the switch S1 entry in the load control table 153 (step C6). The load control unit 14 also sets the ID of the controller C2 in the controller ID 251 of the switch S1 through the secure channel (step C7).

After step C7, the load control unit 14 returns to step C1.

Although in the above processing, the load control unit 14 selects the controller C1 by comparing with a predetermined threshold (first threshold), the controller C1 may be selected in other ways. That is, the load control unit 14 can select the controller 1 whose processing load should be allocated according to any criteria. For example, the load control unit 14 may unconditionally select the controller 1 having the highest processing load as the controller C1.

Although in the above processing, the number of hops is determined, in the case where the number of hops is not determined, the switch 2 with the lowest processing load may be determined as the switch S1. However, determination of the number of hops has the effect of easily distributing the processing load, and also has the effect of preventing the network structure from becoming complicated.

Although in the above description, the controller 1 having the lowest processing load is selected as the controller 1 (C2) to alternately control the switches 2, any controller 1 having a processing load smaller than or equal to a predetermined value may be selected. However, by selecting the controller 1 according to the ascending order of the magnitude of the processing load, the processing load can be optimally balanced.

Next, processing performed by the devices (controller 1, switch 2) when a new switch 2 is added to the OpenFlow network will be described with reference to Figs. 8 and 9 . FIG. 8 is a flowchart showing processing of adding a switch 2 .

First, the packet control unit 21 of the switch 2 to be added (hereinafter, referred to as "object switch 2") obtains the controller information 25 from the adjacent switch 2 (step D1). This controller information obtaining process will be described with reference to FIG. 9 .

The packet control unit 21 of the object switch 2 broadcasts the inquiry packet to the adjacent switch and receives the controller information 25 (step E1). If the packet control unit 21 receives sets of controller information 25 from a plurality of switches 2 (step E2: Yes), it selects the set of controller information 25 including the smallest number of hops 252 (step E3). Then, the packet control unit 21 communicates with the controller 1 through the message control unit 22 and obtains the hop count 252 before contacting the controller 1 (step E4).

Referring again to Fig. 8, the message control unit 22 of the switch 2 having obtained the controller information 25 (step D1) refers to the controller ID 251 in the controller information 25, and establishes a secure channel with the controller 1 identified by the controller ID 251 (step D2).

Then, the message control unit 22 obtains the ID of another controller 1 from the load control table 153 of the controller 1 and establishes a secure channel with those controllers 1 (steps D3, D4).

The load control unit 14 of each controller 1 in the OpenFlow network adds the entry of the subject switch 2 to the load control table 153 (step D5). At this time, the load control unit 14 sets the value of the switch ID 24 of the target switch 2 in the "switch ID" attribute of the load control table 153. The load control unit 14 also sets the value of the hop count 252 of the target switch 2 in the “hop count” attribute of the load control table 153 . The load control unit 14 also sets 0 in each of the “received message count” and “received packet count” attributes of the load control table 153 . Then, the load control unit 14 executes load information update processing (processing of FIG. 6 ) (step D6 ).

Next, referring to FIG. 10 , the processing performed by the devices (controller 1 , switch 2 ) when the switch 2 is deleted from the OpenFlow network will be described. FIG. 10 is a flowchart showing processing of deleting the switch 2 .

The message control unit 22 of the switch 2 to be deleted (hereinafter referred to as "object switch 2") closes the secure channels with all controllers 1 in the OpenFlow network (step F1). In response, the load control unit 14 of each controller 1 deletes the entry of the subject switch 2 from the load control table 153 (step F2 ). Then, the load control unit 14 executes load information update processing (processing of FIG. 6 ) (step F3 ).

Next, a specific example of the process of distributing the processing load of the controller 1 shown in FIG. 7 will be described with reference to FIGS. 11 to 14 . Fig. 11 is a block diagram showing the structure of an OpenFlow network before performing load distribution processing. FIG. 12 is a conceptual diagram showing the structure of the load control table 153 before execution of the load distribution process.

The load control unit 14 calculates the processing load of the controllers (controller A and controller B) in the OpenFlow network (step C1). In this embodiment, the load control unit 14 calculates the processing load of each controller using the following formula.

Processing load of controller C to be calculated = (received message count of controller C/total received message count of all controllers)*(received packet count of switches controlled by this controller C/all switches total received packet count)

Referring to FIG. 12 , the total received message count is 120 and the total received packet count is 800. Therefore, the processing load of controller A is (50/120)*(300/800)≈0.16. Similarly, the processing load of controller B is (70/120)*(500/800)≈0.36. Therefore, the load control unit 14 selects the controller B as the controller with the highest processing load (step C1 ).

The calculation methods described above are merely illustrative, and other methods may be employed. For example, the left or right side (or both sides) of the multiplication formula can be multiplied by a weighting factor. It is also possible to calculate the processing load by addition rather than multiplication. That is, the load control unit 14 only needs to calculate the processing load of each controller 1 according to the information in the load control table 153 . Note that the load control unit 14 can grasp the trend of the processing load of each controller 1 by using at least one of the received message count and the received packet count in the load control table 153, although calculation accuracy will be reduced.

Then, the load control unit 14 determines whether the processing load of the selected controller B is less than or equal to a predetermined threshold (step C2). Assuming that the threshold value is 0.3, the load control unit 14 determines whether the processing load of the controller B is less than or equal to the threshold value (step C2: NO). Then, the load control unit 14 selects the controller A as the controller with the lowest processing load (step C3).

Then, the load control unit 14 obtains the ID of the switch having the least influence on the processing load of the switch controlled by the controller B. Referring to FIG. 12 , the effect of switch C on the processing load is (5/120)*(100/800)≈0.01. The effect of switch D on the processing load is (30/120)*(200/800)≈0.06. The impact of switch E on the processing load is (15/120)*(100/800)≈0.02. The impact of switch F on the processing load is (20/120)*(100/800)≈0.02. Therefore, the load control unit 14 selects the switch C as the switch having the least influence on the processing load (step C4).

Then, the load control unit 14 refers to the load control table 153 and determines whether the hop count of the switch C is the threshold (step C5). Assuming that the threshold is 2, the load control unit 14 determines that the hop count of the switch C is greater than or equal to the threshold (step C5: Yes).

Then, the load control unit 14 sets the ID of the controller A in the "controller ID" attribute of the entry of the switch C of the load control table 153 (step C6). The load control unit 14 also sets the ID of the controller A (switch C7) in the controller ID 251 of the switch C through the secure channel. FIG. 13 shows the load control table 153 at the point in time when this processing is completed. Underlined parts indicate controller changes. Although the number of hops may vary depending on the controller, in this embodiment it is assumed that the number of hops does not change.

Then, the load control unit 14 calculates the processing loads of the controllers (controller A and controller B) in the OpenFlow network again (step C1).

Referring to FIG. 13 , the total received message count is 120, and the total received packet count is 800. Therefore, the processing load of controller A is (55/120)*(400/800)≈0.23. Similarly, the processing load of controller B is (65/120)*(400/800)≈0.27. Therefore, the load control unit 14 selects the controller B as the controller with the highest processing load (step C1 ).

Then, the load control unit 14 determines whether the processing load of the selected controller B is less than or equal to a predetermined threshold (step C2). Since the threshold is 0.3, the load control unit 14 determines that the processing load of the controller B is less than or equal to the threshold (step C2: Yes), and ends the process. Fig. 14 is a block diagram showing the structure of an OpenFlow network after performing load distribution processing.

Next, effects of the OpenFlow network according to the present embodiment will be described. The load control unit 14 distributes the processing load of the controller 1 according to the use state of the switch 2 or the topology of the OpenFlow network. Thereby, it is possible to prevent the processing load from being unevenly applied to a specific controller 1 and to distribute the load accurately.

Furthermore, when the switch 2 is added to or deleted from the OpenFlow network, the controller 1 updates the topology information (executes the above-mentioned steps B1 to B7) before distributing the load. Thereby, load can be distributed after updating the connection state of each device in the OpenFlow network.

second embodiment

The controller 1 according to the second embodiment of the present invention is characterized in that the controller 1 considers the number of switches controlled by each controller in the load distribution process of FIG. 7 . Hereinafter, differences between the second embodiment and the first embodiment will be described.

In the above-mentioned FIG. 7 , the load control unit 14 calculates the processing load of each controller 1 using the following formula.

Processing load of controller C to be calculated = (number of switches controlled by this controller C/number of all switches in the OpenFlow network)*(count of received messages of controller C/total of all controllers received message count)*(received packet count of switches controlled by this controller C/total received packet count of all switches)

Next, referring again to FIGS. 11 to 14 , a specific example of the process of distributing the load of the controller 1 according to the present embodiment will be described ( FIG. 7 ). As described above, FIG. 11 is a block diagram showing the structure of the OpenFlow network before the load distribution process is performed. FIG. 12 is a conceptual diagram showing the structure of the load control table 153 before execution of the load distribution process.

Referring to Figure 12, the total switch count is 6 and the total received message count is 120. Therefore, the processing load of controller A is (2/6)*(50/120)*(300/800)≈0.05. Similarly, the processing load of controller B is (4/6)*(70/120)*(500/800)≈0.24. Therefore, the load control unit 14 selects the controller B as the controller with the highest processing load (step C1 ).

Then, the load control unit 14 determines whether the processing load of the selected controller B is less than or equal to a predetermined threshold (step C2). Assuming that the threshold value is 0.2, the load control unit 14 determines that the processing load of the controller B is not less than or equal to the threshold value (step C2: NO). Then, the load control unit 14 selects the controller A as the controller with the lowest processing load (step C3).

Then, the load control unit 14 obtains the ID of the switch having the least influence on the processing load of the switch controlled by the controller B. Based on FIG. 12 , the load control unit 14 calculates the influence on the processing load as follows.

Switch C: (5/120)*(100/800)

Switch D: (30/120)*(200/800)

Switch E: (15/120)*(100/800)

Switch F: (20/120)*(100/800)

Therefore, the load control unit 14 selects the switch C as the switch having the least influence on the processing load (step C4). Then, the load control unit 14 refers to the load control table 153 and determines whether the hop count of the switch C is greater than or equal to a threshold (step C5). Assuming that the threshold is 2, the load control unit 14 determines that the hop count of the switch C is greater than or equal to the threshold (step C5: Yes).

Then, the load control unit 14 sets the ID of the controller B in the "controller ID" attribute of the entry of the switch C of the load control table 153 (step C6). The load control unit 14 also sets the ID of the controller B (switch C7) in the controller ID 251 of the switch C through the secure channel. FIG. 13 shows the load control table 153 at the point in time when this processing is completed. Underlined parts indicate controller changes.

The load control unit 14 calculates the processing loads of the controllers (controller A and controller B) in the OpenFlow network again (step C1).

Referring to FIG. 13 , it can be seen that the total switch count is 6, the total received message count is 120, and the total received packet count is 800. Therefore, the processing load of controller A is (3/6)*(55/120)*(400/800)≈0.11. Similarly, the processing load of controller B is (3/6)*(65/120)*(400/800)≈0.13. Therefore, the load control unit 14 selects the controller B as the controller with the highest processing load (step C1 ).

Then, the load control unit 14 determines whether the processing load of the selected controller B is less than or equal to a predetermined threshold (step C2). Since the threshold is 0.2, the load control unit 14 determines that the processing load of the controller B is less than or equal to the threshold (step C2: Yes), and ends the process. Fig. 14 is a block diagram showing the structure of an OpenFlow network after performing load distribution processing.

Also in this embodiment, it is possible to avoid uneven application of load to a specific controller 1 and to distribute the load accurately. As can be seen above, the load control unit 14 also considers the relationship between the total switch count and the number of switches controlled by each controller 1, and then distributes the load. Thereby, it is possible to perform load distribution that also considers the connection state of the network (ie, avoid load distribution in which the number of switches controlled by each controller is uneven in the network).

Although the present invention has been described for its embodiments, the present invention is not limited to its structure. Of course, the present invention includes changes, modifications or combinations made to the embodiments by those skilled in the art without departing from the scope of the claims of the present application.

The processing performed by the processing units (message control unit 11, path control unit 12, topology update unit 13, and load control unit 14) of the controller 1 can be embodied as a program running on any computer. The program can be stored in various types of non-transitory computer-readable media and provided to a computer. Examples of non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic storage media (e.g., flexible disk, magnetic tape, hard drive), magneto-optical storage media (e.g., magneto-optical disk), compact disk read-only memory (CD-ROM), CD-R, CD- R/W, semiconductor memory such as mask ROM, programmable ROM (PROM), erasable PROM (EPROM), flash ROM, and random access memory (RAM). Can be accessed by various types of transient computers Read medium, the program is provided to the computer. Examples of the transient computer readable medium include electrical signals, optical signals and electromagnetic waves. The transient computer readable medium can provide the program to the computer.

FIG. 15 is a diagram showing an example hardware configuration of the controller 1 . The controller 1 includes a central processing unit (CPU) 401 and a memory 402 . A CPU 401 and a memory 402 are connected via a bus to a hard disk drive (HDD) 403 serving as an auxiliary storage device. A storage medium such as the HDD 403 can store a computer program for cooperating with an operating system, providing instructions to the CPU 401 and the like, and executing functions of units of the CPU 401 and the like. That is, when this program is loaded into the memory 402, the blocks of the controller 1 are formed, and then, the CPU 401 executes processing according to the program and cooperates with other hardware components. Then, when the CPU 401 executes a predetermined program, the controller 1 executes processing.

Fig. 16 is a block diagram schematically showing the present invention. The OpenFlow network includes multiple controllers 1 and multiple switches 2 . Each controller 1 includes a load control table 153 and a load control unit 14 .

The load control table 153 controls the number of messages that each switch 2 in the OpenFlow network has transmitted to the controller that controls the switch 2 within a predetermined time and the number of packets that each switch 2 has received within a predetermined time. at least one. That is, the load control table 153 holds load information dedicated to the OpenFlow network. When a predetermined event occurs, the load control unit 14 refers to the load control table 153 and detects a controller 1 having a processing load higher than or equal to the first threshold. For example, the load control unit 14 calculates the processing load by multiplying the received packet count and the received message count. Then, the load control unit 14 brings at least one of the switches 2 controlled by the detected controller 1 under the control of another controller 1 .

According to the above structure, the load control unit 14 can distribute the load of the controller 1 according to the use state of the switch 2 or the topology of the OpenFlow network. That is, it is possible to prevent the load from being unevenly applied to a specific controller 1 .

Although in the above description, each controller 1 includes the load control table 153 and the load control unit 14, other configurations are possible. For example, a control device for instructing each controller 1 to control the switch 2 may be provided in an OpenFlow network. This control device includes a load control table 153 and a load control unit 14 . The control device calculates the processing load of each controller 1 and brings the switch 2 controlled by the controller 1 with high processing load under the control of another controller 1 . This structure also produces the above-mentioned effects.

This application claims priority based on Japanese Patent Application No. 2012-020695 filed on February 2, 2012, the disclosure of which is incorporated herein in its entirety.

List of reference signs

1 controller

11 message control unit

12 path control unit

13 topology update unit

14 Load control unit

15 Network information storage unit

151 path information

152 topology information

153 Load control table

2 switches

21 Group control unit

22 message control unit

23 flow table

24 Switch ID

25 Controller information

251 Controller ID

252 hops

3 terminal

401 CPU

402 memory

403 HDD

Claims (25)

1. a controller, described controller is for being controlled at some in multiple switches of open flows network, and described controller comprises:

Load control table, described load control table is configured to control at least one in following: each in the described switch in open flows network in the scheduled time to the number of message and the number of the grouping that described switch has received in the scheduled time of controller transmission of controlling described switch; And

Load control device, described load control device is configured in the time that scheduled event occurs, carry out based on described load control table the controller that Check processing load should be assigned with, and under at least one in the switch that makes to be controlled by detected controller control in another controller.

2. controller according to claim 1, wherein,

Described processing load is numerical information, the high value instruction higher load of described numerical information, and

Described load control device detects the controller having greater than or equal to the processing load of first threshold.

3. controller according to claim 2, wherein, following controller is chosen as described another controller by described load control device: this controller has relatively low processing load.

4. controller according to claim 2, wherein,

Described load control table control about in the described switch in open flows network each and control the information of the jumping figure between the controller of described switch, and

Described load control device is chosen as following switch by least one switch under the control in described another controller: this switch has the impact relatively little on described processing load and has the jumping figure that is more than or equal to Second Threshold.

5. according to the controller described in claim 2 or 3, wherein, described load control device is by making the number of described message and the number of received grouping multiply each other to calculate described processing load.

6. according to the controller described in any one in claim 1 to 5, wherein, described scheduled event comprises in following: the spending to, open flows network is added switch and delete switch from open flows network of the scheduled time.

7. according to the controller described in any one in claim 1 to 6, wherein, the number of the number of the number of the message of described load control device based on received and received grouping and the switch controlled by each controller, the processing load of calculating described controller.

8. according to the controller described in any one in claim 1 to 7, further comprise topological updating device, described topological updating device is configured to control the topological information about open flows network,

Wherein, in the time that described scheduled event occurs, described topological updating device detects has the controlled exchange machine that connects fault, and before described load control device is carried out processing, eliminates the connection fault of detected switch.

9. for the method for the load of dispensing controller, some in the multiple switches in described controller control open flows network, described method comprises:

Control step, the control table of described control step control load, described load control table comprises at least one in following: each in the described switch in open flows network in the scheduled time to the number of message and the number of the grouping that described switch has received in the scheduled time of controller transmission of controlling described switch; And

Load control step, in the time that scheduled event occurs, carrys out based on described load control table the controller that Check processing load should be assigned with, and under at least one in the switch that makes to be controlled by detected controller control in another controller.

10. method according to claim 9, wherein,

Described processing load is numerical information, the high value instruction higher load of described numerical information, and

Described load control step comprises that detection has the controller greater than or equal to the processing load of first threshold.

11. methods according to claim 10, wherein, described load control step comprises following controller is chosen as to described another controller: this controller has relatively low processing load.

12. methods according to claim 11, wherein,

Described load control table control about in the described switch in open flows network each and control the information of the jumping figure between the controller of described switch, and

Described load control step comprises following switch is chosen as at least one switch under the control in described another controller: this switch has the impact relatively little on described processing load and has the jumping figure that is more than or equal to Second Threshold.

13. according to the method described in claim 10 or 11, and wherein, described load control step comprises that the number of number by making described message and received grouping multiplies each other to calculate described processing load.

14. according to the method described in any one in claim 9 to 13, and wherein, described scheduled event comprises in following: the spending to, open flows network is added switch and delete switch from open flows network of the scheduled time.

15. according to claim 10 to the method described in any one in 14, wherein, described load control step comprises the number of the message based on received and the number of received grouping and the number of the switch controlled by each controller, the processing load of calculating each controller.

16. 1 kinds of stored program non-instantaneous computer-readable mediums, described program is used for making computer to carry out the method for the load of dispensing controller, some in the multiple switches in described controller control open flows network, described method comprises:

Control step, the control table of described control step control load, described load control table comprises at least one in following: each in the described switch in open flows network in the scheduled time to the number of message and the number of the grouping that described switch has received in predetermined amount of time of controller transmission of controlling described switch; And

Load control step, in the time that scheduled event occurs, carrys out based on described load control table the controller that Check processing load should be assigned with, and under at least one in the switch that makes to be controlled by detected controller control in another controller.

17. non-instantaneous computer-readable mediums according to claim 16, wherein,

Described processing load is numerical information, the high value instruction higher load of described numerical information, and

Described load control step comprises that detection has the controller greater than or equal to the processing load of first threshold.

18. non-instantaneous computer-readable mediums according to claim 17, wherein, described load control step comprises following controller is chosen as to described another controller: this controller has relatively low processing load.

19. non-instantaneous computer-readable mediums according to claim 18, wherein,

Described load control table control about in the described switch in open flows network each and control the information of the jumping figure between the controller of described switch, and

Described load control step comprises following switch is chosen as at least one switch under the control in described another controller: this switch has the impact relatively little on described processing load and has the jumping figure that is more than or equal to Second Threshold.

20. according to the non-instantaneous computer-readable medium described in claim 17 or 18, and wherein, described load control step comprises that the number of number by making described message and received grouping multiplies each other to calculate described processing load.

21. according to claim 16 to the non-instantaneous computer-readable medium described in any one in 20, wherein, described scheduled event comprises in following: the spending to, open flows network is added switch and delete switch from open flows network of the scheduled time.

22. non-instantaneous computer-readable mediums according to claim 21, wherein, described load control step comprises to be worked as described scheduled event, when switch is added to open flows network or delete switch from open flows network, upgrade described load control table, and compare with described first threshold subsequently.

23. according to claim 16 to 22 any one described in non-instantaneous computer-readable medium, wherein, described load control step comprises the number of the message based on received and the number of received grouping and the number of the switch controlled by each controller, the processing load of calculating each controller.

24. 1 kinds of computer systems, comprising:

Multiple switches, each in described multiple switches is configured to divide into groups at open flows network repeating based on stream table; And

Multiple controllers, each in described multiple controllers is configured to control some in described switch,

Wherein, each in described controller comprises:

Load control table, described load control table is configured to control at least one in following: each in the described switch in open flows network in the scheduled time to the number of message and the number of the grouping that described switch has received in the scheduled time of controller transmission of controlling described switch; And

Load control device, described load control device is configured in the time that scheduled event occurs, carry out based on described load control table the controller that Check processing load should be assigned with, and under at least one in the switch that makes to be controlled by detected controller control in another controller.

25. 1 kinds for distributing the control appliance of load of multiple controllers, the switch in described controller control open flows network, and described control appliance comprises:

Load control table, described load control table is configured to control at least one in following: each in the described switch in open flows network in the scheduled time to the number of message and the number of the grouping that described switch has received in the scheduled time of controller transmission of controlling described switch; And

Load control device, described load control device is configured in the time that scheduled event occurs, carry out based on described load control table the controller that Check processing load should be assigned with, and under at least one in the switch that makes to be controlled by detected controller control in another controller.